Method and apparatus for monitoring the surface contact of a neutral electrode of a HF-surgical apparatus
First Claim
1. A method for monitoring the neutral electrode of a HF-surgical apparatus for sufficiency of surface area contact with a body, in which the neutral electrode consists of an odd number of at least three partial electrodes and in which a comparison dependent alarm signal is generated in the event of insufficient surface area contact with said body, comprising the following steps:
- applying HF-currents to three of said partial electrodes through said body;
sensing the HF-currents accepted by said three partial electrodes and forming electrical partial current signals corresponding to respective ones of said sensed accepted HF-currents;
combining three different pairs of said electrical partial current signals for developing three combined electrical signals;
comparing the level of each of said three combined electrical signals with a pre-set limit value, thereby obtaining three comparison signals;
developing a logic OR signal from said three comparison signals; and
generating an alarm signal dependent upon said logic OR signal.
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Accused Products
Abstract
The HF-current generator of an electrosurgical apparatus has one terminal connected to an active electrode and an additional terminal connected to a neutral electrode. The neutral electrode consists of at least two partial electrodes which are individually connected via connecting leads to respective current meters for measuing the partial currents in the respective connecting leads. The output side of the current meters are connected to a logic element that is provided for combining the partial currents and which provides a logic signal that is a function of their combination. A ratio generator is preferably provided as the logic element to develop a logic signal that is a function of the ratio of the partial currents. A comparator for comparing the logic signal with pre-set limit value is associated with the logic element. The output signal of the comparator is used as an alarm signal to actuate an alarm or a protective means for a patient in contact with the neutral electrode.
257 Citations
23 Claims
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1. A method for monitoring the neutral electrode of a HF-surgical apparatus for sufficiency of surface area contact with a body, in which the neutral electrode consists of an odd number of at least three partial electrodes and in which a comparison dependent alarm signal is generated in the event of insufficient surface area contact with said body, comprising the following steps:
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applying HF-currents to three of said partial electrodes through said body; sensing the HF-currents accepted by said three partial electrodes and forming electrical partial current signals corresponding to respective ones of said sensed accepted HF-currents; combining three different pairs of said electrical partial current signals for developing three combined electrical signals; comparing the level of each of said three combined electrical signals with a pre-set limit value, thereby obtaining three comparison signals; developing a logic OR signal from said three comparison signals; and generating an alarm signal dependent upon said logic OR signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Circuit arrangement for monitoring the neutral electrode of a HF-surgical apparatus for sufficiency of surface contact with a body when said neutral electrode comprises an odd number of at least three partial electrodes adapted to receive said body between said partial electrodes and said active electrode, comprising:
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a HF-current generator having a first and a second terminal, said first terminal for coupling said generator to said active electrode and said second terminal for coupling said generator to said neutral electrode; current meter means for connection between each of said three partial electrodes and said HF current generator for measuring at least three partial currents developed in said at least three partial electrodes; combining means coupled to the output side of said current meter means for combining the measured partial currents and generating at least three combined electrical signals that are a function of the combination; a plurality of comparator means coupled to said combining means for receiving respective ones of said combined electrical signals; a comparison element coupled to each of said comparator means for comparing respective ones of said combined electrical signals with a pre-set limit value for developing an output signal from each of said comparator means; and logic means having an input coupled to each of said comparator means for combining said output signals of said comparator means and providing at an output thereof an alarm signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A circuit arrangement for monitoring the neutral electrode of a HF-surgical apparatus for sufficiency of surface contact with a body, comprising:
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an active electrode; a neutral electrode comprising three partial electrodes and adapted to receive said body between said partial electrodes and said active electrode; a HF-current generator having a first and a second terminal, said first terminal coupling said generator to said active electrode and said second terminal coupling said generator to said neutral electrode; a current meter connected with each partial electrode and said second terminal for measuring partial currents developed in said partial electrodes; a combining element coupled to the output side of each current meter for combining the measured partial currents and generating at an output a combined electrical signal that is a function of the combination; a comparator coupled to the output of each of said combining elements for receiving a respective one of said combined electrical signals; a comparison element coupled with each of said comparators for comparing a respective one of said combined electrical signals with a pre-set limit value for developing an output signal from each of said comparators; and logic means coupled with each of said comparators and responsive to said output signals therefrom for developing an alarm signal. - View Dependent Claims (21, 22, 23)
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Specification